1. Field of the Invention
The present invention generally relates to manufacturing methods of semiconductor devices, and more specifically, to a manufacturing method of a semiconductor device wherein a transparent member is provided above a light receiving part provided on a main surface of a semiconductor element.
2. Description of the Related Art
A solid-state image sensing device formed by packaging and modularizing a solid-state image sensor with a transparent member such as glass, a wiring board, wiring connecting the solid-state image sensor and the wiring board, sealing resin, and others, is well-known. Here, the solid-state image sensing device is, for example, an image sensor such as a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS).
In such a solid-state image sensing device, if a foreign body such as dust is situated on a light receiving surface of the solid-state image sensor, the foreign body blocks incident light so that the foreign body is reflected in a monitor picture as a black point.
Because of this, it is attempted to manufacture the solid-state image sensing device in a clean room in order to prevent entry of foreign bodies. However, it is difficult to realize the perfect situation. Hence, a structure is applied where a surface protection transparent member such as glass is provided above the light receiving surface of the solid-state image sensor so that the light receiving surface of the solid-state image sensor is sealed in an initial step of a manufacturing process of the solid-state image sensing device.
FIG. 1 is a first view showing a manufacturing process of a related art solid-state image sensing device. FIG. 2 is a second view showing the manufacturing process of the related art solid-state image sensing device.
While the subject of such a manufacturing process is a semiconductor wafer on which plural solid-state image sensors are formed, a single solid-state image sensor is illustrated in FIG. 1 and FIG. 2. Illustrations of other solid-state image sensing elements situated in the periphery of this solid-state image sensor are omitted in FIG. 1 and FIG. 2.
Referring to FIG. 1, a back grinding process is applied to a rear surface of a semiconductor wafer 100 having a surface (main surface) where plural image sensors are formed via a designated wafer process. At this time, the surface of the semiconductor wafer 100 where a light receiving element area 2 is formed is protected by a BG (Back Grinding) tape 3. In this state, the rear surface of the semiconductor wafer 100 is ground (See FIG. 1-(A).
On the other hand, a glass plate 4 is prepared as a transparent member for protecting the light receiving element area 2.
A large-sized glass plate is adhered to a dicing tape 5 and pieces of the large-sized glass plate are made by a cutting method using a blade so that the glass plate 4 is made (See FIG. 1-(B)).
After that, while the BG tape 3 shown in FIG. 1-(A) adhered on the surface of the semiconductor wafer 1 is removed, the dicing tape 5 is adhered on the rear surface of the semiconductor wafer 100 (See FIG. 1-(C)).
Next, a transparent adhesive 6 is selectively applied on the light receiving element area 2 in the image sensors on the upper surface of the semiconductor wafer 100 (See FIG. 1-(D)).
Then, the glass pate 4 being large sized is removed from the dicing tape 5 so as to be mounted above the light receiving element area 2 in the image sensor of the semiconductor wafer 100 via the transparent adhesive 6 (See FIG. 1-(E)). This process is applied to a good semiconductor chip of the semiconductor wafer 100.
After that, a dicing process is applied so that the semiconductor wafer 100 is diced into pieces. As a result of this a semiconductor chip 1 that is an image sensor is formed (See FIG. 2-(F)).
The semiconductor chip 1 is die bonded on a supporting substrate (wiring board) 7 via die application material 8 (FIG. 2-(G)). An electrode terminal 9 of the semiconductor chip 1 is connected to an electrode terminal 11 of the supporting substrate 7 by a bonding wire 10 (FIG. 2-(H)).
After that, the semiconductor chip 1, the bonding wire 10, and others except an upper part of the glass plate 4, are sealed by sealing resin 12 (See FIG. 2-(I))
Then, a solder ball as an outside connection terminal 13 is provided on a rear surface of the supporting substrate 7, so that a solid-state image sensing device 14 is completed (See FIG. 2-(J)).
Modified examples of the manufacturing processes discussed with reference to FIG. 1 and FIG. 2 have been suggested.
FIG. 3 is a view showing a first modified example of the manufacturing process shown in FIG. 1 and FIG. 2. FIG. 4 is a view showing a second modified example of the manufacturing process shown in FIG. 1 and FIG. 2.
In the first modified example shown in FIG. 3, a large-sized glass plate 4′ having an area equal to or greater than the area of the semiconductor wafer 100 is mounted and fixed above the semiconductor wafer 100 (See FIG. 3-(E′)).
Next, a dicing process is applied to the glass plate 4′ and the semiconductor wafer 100 in a lump for making pieces so that the semiconductor chip 1 is formed (See FIG. 3-(F′)-(1)).
After that, only the glass plate 4′ is cut so as to have a designate size corresponding to the light receiving element area 2 by applying the dicing process again (See FIG. 3-(F′)-(2)).
On the other hand, in the second modified example shown in FIG. 4, after the large-sized glass plate 4′ having an area equal to or greater than the area of the semiconductor wafer 100 is mounted and fixed above the semiconductor wafer 100, a dicing process is applied to only the glass plate 4′ so that the glass plate 4′ is cut into a designated size corresponding to the light receiving element area 2 (See FIG. 4-(F″)-(1)) and then the semiconductor wafer 100 is divided for making the pieces of the semiconductor chips 1 (See FIG. 4-(F″)-(2)). See in Japanese Laid-Open Patent Application Publication No. 2004-172249 and Japanese Laid-Open Patent Application Publication No. 2004-296738.
Thus, in the manufacturing methods shown in FIG. 1 and FIG. 2, the transparent adhesive 6 is selectively applied on the light receiving element areas of plural semiconductor chips of the semiconductor wafer 100 so that the glass plate 4 being of large size is mounted by using the transparent adhesive 6. See FIG. 1-(D) and FIG. 1-(E).
Since this process is implemented in a semiconductor chip unit, the number of processes is increased. This tendency is remarkable when the size of the semiconductor chip 1 is small.
In addition, since the glass plate 4 is provided above the light receiving element area on the surface of the semiconductor chip 1, a manufacturing apparatus and method having high positioning precision are required.
In order to prevent position shift of the glass plate 4 after the glass plate 4 is mounted, it is necessary to control the amount of the transparent adhesive 6 applied to the surface of the semiconductor wafer 100. In addition, voids should not be contained in the applied transparent adhesive 6.
If it is attempted to solve the above-mentioned problems in the manufacturing processes shown in FIG. 1 and FIG. 2, the manufacturing cost for the solid-state image sensing device 14 may increase.
On the other hand, in the manufacturing process shown in FIG. 3, while the above-mentioned problems of the manufacturing processes shown in FIG. 1 and FIG. 2 may be solved, since the dicing process is applied to plural different kinds of materials, glass plate 4′ and the semiconductor wafer 100 in the same step, the processing quality may be degraded.
If the processing speed is decreased in order to prevent this, the processing ability may be degraded.
Furthermore, in a process for dicing only the glass plate 4′, the transparent adhesive 6 is not provided in the vicinity of the end part of the glass plate 4′ so that the process is unstable and implemented where there is no support. Hence, the processing quality may be degraded.
In addition, in the process for dicing only the glass plate 4′, if the transparent resin 6 is spread to the outside of an area where the transparent resin should be provided, the transparent adhesive 6 is cut together with the glass plate 4′. Therefore, the dicing blade may become clogged due to the transparent adhesive so that unnecessary cracks may be formed in the glass plate 4′.
Furthermore, in the manufacturing process shown in FIG. 4, first the dicing process is applied to only the glass plate 4′ (See FIG. 4-(F″)-(1)) and then the semiconductor wafer 100 is divided so that pieces of the semiconductor chips 1 are made (See FIG. 4-(F″)-(2)).
Therefore, it is necessary to prepare both the dicing blade for cutting the glass plate 4′ and the dicing blade for cutting the semiconductor wafer 100 and process them in separated steps. Hence, the number of steps may be increased.